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Nat Med ; 25(12): 1839-1842, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31768065


Histiocytoses are clonal hematopoietic disorders frequently driven by mutations mapping to the BRAF and MEK1 and MEK2 kinases. Currently, however, the developmental origins of histiocytoses in patients are not well understood, and clinically meaningful therapeutic targets outside of BRAF and MEK are undefined. In this study, we uncovered activating mutations in CSF1R and rearrangements in RET and ALK that conferred dramatic responses to selective inhibition of RET (selpercatinib) and crizotinib, respectively, in patients with histiocytosis.

Quinase do Linfoma Anaplásico/genética , Histiocitose/genética , Proteínas Proto-Oncogênicas c-ret/genética , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Adolescente , Adulto , Aminopiridinas/farmacologia , Benzotiazóis/farmacologia , Criança , Pré-Escolar , Feminino , Genoma Humano , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/patologia , Histiocitose/tratamento farmacológico , Histiocitose/patologia , Humanos , Lactente , Masculino , Mutação , Ácidos Picolínicos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Piridinas/farmacologia , Pirróis/farmacologia , Receptores Proteína Tirosina Quinases/genética , Gêmeos Monozigóticos , Sequenciamento Completo do Exoma , Adulto Jovem
Nat Chem Biol ; 15(6): 641-649, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31011214


Clathrin-mediated endocytosis (CME) is a highly conserved and essential cellular process in eukaryotic cells, but its dynamic and vital nature makes it challenging to study using classical genetics tools. In contrast, although small molecules can acutely and reversibly perturb CME, the few chemical CME inhibitors that have been applied to plants are either ineffective or show undesirable side effects. Here, we identify the previously described endosidin9 (ES9) as an inhibitor of clathrin heavy chain (CHC) function in both Arabidopsis and human cells through affinity-based target isolation, in vitro binding studies and X-ray crystallography. Moreover, we present a chemically improved ES9 analog, ES9-17, which lacks the undesirable side effects of ES9 while retaining the ability to target CHC. ES9 and ES9-17 have expanded the chemical toolbox used to probe CHC function, and present chemical scaffolds for further design of more specific and potent CHC inhibitors across different systems.

Derivados de Benzeno/farmacologia , Cadeias Pesadas de Clatrina/antagonistas & inibidores , Endocitose/efeitos dos fármacos , Arabidopsis , Derivados de Benzeno/química , Cadeias Pesadas de Clatrina/metabolismo , Humanos , Modelos Moleculares , Estrutura Molecular , Tiofenos/farmacologia
Plant Cell ; 30(10): 2573-2593, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30018157


Small GTP-binding proteins from the ADP-ribosylation factor (ARF) family are important regulators of vesicle formation and cellular trafficking in all eukaryotes. ARF activation is accomplished by a protein family of guanine nucleotide exchange factors (GEFs) that contain a conserved catalytic Sec7 domain. Here, we identified and characterized Secdin, a small-molecule inhibitor of Arabidopsis thaliana ARF-GEFs. Secdin application caused aberrant retention of plasma membrane (PM) proteins in late endosomal compartments, enhanced vacuolar degradation, impaired protein recycling, and delayed secretion and endocytosis. Combined treatments with Secdin and the known ARF-GEF inhibitor Brefeldin A (BFA) prevented the BFA-induced PM stabilization of the ARF-GEF GNOM, impaired its translocation from the Golgi to the trans-Golgi network/early endosomes, and led to the formation of hybrid endomembrane compartments reminiscent of those in ARF-GEF-deficient mutants. Drug affinity-responsive target stability assays revealed that Secdin, unlike BFA, targeted all examined Arabidopsis ARF-GEFs, but that the interaction was probably not mediated by the Sec7 domain because Secdin did not interfere with the Sec7 domain-mediated ARF activation. These results show that Secdin and BFA affect their protein targets through distinct mechanisms, in turn showing the usefulness of Secdin in studies in which ARF-GEF-dependent endomembrane transport cannot be manipulated with BFA.

Arabidopsis/efeitos dos fármacos , Fatores de Troca do Nucleotídeo Guanina/antagonistas & inibidores , Ftalazinas/farmacologia , Piperazinas/farmacologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brefeldina A/farmacologia , Endocitose/efeitos dos fármacos , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Plantas Geneticamente Modificadas , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Transporte Proteico , Vacúolos/efeitos dos fármacos , Vacúolos/metabolismo
Nat Commun ; 7: 13228, 2016 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-27819269


Subversion of the host immune system by viruses is often mediated by molecular decoys that sequester host proteins pivotal to mounting effective immune responses. The widespread mammalian pathogen parapox Orf virus deploys GIF, a member of the poxvirus immune evasion superfamily, to antagonize GM-CSF (granulocyte macrophage colony-stimulating factor) and IL-2 (interleukin-2), two pleiotropic cytokines of the mammalian immune system. However, structural and mechanistic insights into the unprecedented functional duality of GIF have remained elusive. Here we reveal that GIF employs a dimeric binding platform that sequesters two copies of its target cytokines with high affinity and slow dissociation kinetics to yield distinct complexes featuring mutually exclusive interaction footprints. We illustrate how GIF serves as a competitive decoy receptor by leveraging binding hotspots underlying the cognate receptor interactions of GM-CSF and IL-2, without sharing any structural similarity with the cytokine receptors. Our findings contribute to the tracing of novel molecular mimicry mechanisms employed by pathogenic viruses.

Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Interleucina-2/imunologia , Parapoxvirus/imunologia , Proteínas Virais/imunologia , Cristalografia por Raios X , Fator Estimulador de Colônias de Granulócitos e Macrófagos/química , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Células HEK293 , Interações Hospedeiro-Patógeno/imunologia , Humanos , Interleucina-2/química , Interleucina-2/metabolismo , Modelos Moleculares , Complexos Multiproteicos/química , Complexos Multiproteicos/imunologia , Complexos Multiproteicos/metabolismo , Parapoxvirus/metabolismo , Infecções por Poxviridae/imunologia , Infecções por Poxviridae/metabolismo , Infecções por Poxviridae/virologia , Ligação Proteica , Proteínas Virais/química , Proteínas Virais/metabolismo
Structure ; 23(9): 1621-1631, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26235028


Human colony-stimulating factor 1 receptor (hCSF-1R) is unique among the hematopoietic receptors because it is activated by two distinct cytokines, CSF-1 and interleukin-34 (IL-34). Despite ever-growing insights into the central role of hCSF-1R signaling in innate and adaptive immunity, inflammatory diseases, and cancer, the structural basis of the functional dichotomy of hCSF-1R has remained elusive. Here, we report crystal structures of ternary complexes between hCSF-1 and hCSF-1R, including their complete extracellular assembly, and propose a mechanism for the cooperative human CSF-1:CSF-1R complex that relies on the adoption by dimeric hCSF-1 of an active conformational state and homotypic receptor interactions. Furthermore, we trace the cytokine-binding duality of hCSF-1R to a limited set of conserved interactions mediated by functionally equivalent residues on CSF-1 and IL-34 that play into the geometric requirements of hCSF-1R activation, and map the possible mechanistic consequences of somatic mutations in hCSF-1R associated with cancer.

Cristalografia por Raios X , Fator Estimulador de Colônias de Macrófagos/química , Fator Estimulador de Colônias de Macrófagos/metabolismo , Receptor de Fator Estimulador de Colônias de Macrófagos/química , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Sítios de Ligação , Ativação Enzimática , Humanos , Modelos Moleculares , Fosforilação , Espalhamento a Baixo Ângulo , Transdução de Sinais , Difração de Raios X